1. Field of the Invention
This invention generally relates to an apparatus for providing tactile graphic images or alphanumeric text for the visually impaired. More specifically, the invention relates to a system for producing tactile drawings and braille text from data generated by conventional computer graphics software.
2. Description of the Prior Art
A number of methods have been developed to allow blind persons or persons with serious visual impairments to lead normal and independent lives. Continuous effort has been deployed in ensuring that blind people can have access to literary works. For example, the development of Braille language by Louis Braille was a major breakthrough to allow the blind person to "read" by tactile recognition of series of pattern points corresponding to standard alphabets. More recently, further efforts have yielded various computerized Braille language display systems. There are also known computerized systems which scan pages of conventional text and through the use of a speech synthesizer read out the words for a blind user.
However, the systems described above do not allow a blind person to have access to certain graphic images or figures. But, for example, a blind person will not be able to read a conventional road map or to discern printed images. Some rudimentary means have been employed to prepare tactile images which may be recognize by tactile perception with fingers. The most rudimentary example is the gluing of string on paper whereby tactile shapes may be created. Other methods include creating embossed master from which tactile shapes in thermoplastic material can be made. Such methods commonly involve the embossing of graphics and/or shapes in a light gage aluminum foil and the subsequent step of heating a thermoplastic sheet and vacuum forming it over the master.
It is also noted that some tactile Braille display systems using raised and retractable array of pins can be used to display tactile images. For example, such systems are described in U.S. Pat. No. 4,772,205 and U.S. Pat. No. 4,871,992. However, graphic displays created by such systems are ephemeral and are not portable. The user must have access to the complicated and generally very expensive graphic display equipment. Moreover, the resolution and size of graphic display provided by such systems is limited.
Consequently, there remains an important need for a system which will efficiently and inexpensively prepare tactile graphic images on any suitable reference surface such as a sheet of paper.